CPU usage over 100%

English Applications
1

Could someone please explain how CPU usage can exceed 100% as indicated by “top” below?



  PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND                            
 2271 ion       20   0 2843084  75156  21080 S 117.6 1.853   0:27.53 Vcc.exe                            
 1177 root      20   0  235552  55072  14140 S 7.310 1.358   1:23.32 Xorg                               
 1417 ion        9 -11  584436  14364  11528 S 5.316 0.354   1:35.89 pulseaudio                         
 2274 ion       20   0   17640   7648    644 S 2.658 0.189   0:00.71 wineserver

Thanks in advance.

2

You have more than 1 core in the system and the application has multi-core support - top shows each core as 100%.

Example;
You have 8 cores and your application has proper parallel support - it has 4 threads that are using maximum available calculation power, thus your application shows up as using 400% of CPU (out of 800% available)

Here’s an example of lbzip2 compressing a file with 4 threads in use (-n 4) on an 8-core system:
http://i.imgur.com/cjSmdkl.png

3

Thanks for the clear explanation. I am so far behind the times that I have a two core processor and didn’t know it.